Aircraft evacuation slide with thermally actuated gas relief valve

Abstract

An inflation valve for use with an inflatable emergency evacuation slide includes a thermally actuated gas relief valve having an exhaust port the effective size of which increases with increasing temperature. The exhaust port is metered by a valve member. The valve member position is controlled by a thermal actuator that lengthens with increasing temperature. At high ambient temperatures, the valve member moves to uncover the exhaust port thereby increasing the effective size of the port so that a large percentage of the inflation gas is vented. At low ambient temperatures the valve member moves to cover the exhaust port, thereby decreasing effective size of the exhaust port so that little or no inflation gas is vented.

1. An inflatable aircraft evacuation slide system comprising:
 an inflatable evacuation slide stored in an undeployed condition; 
 a source of inflation gas for inflating said inflatable evacuation slide; 
 a control valve, said control valve comprising;
 a valve body defining an interior chamber and an inlet port in fluid communication with said source of inflation gas, 
 a primary valve member, said primary valve member disposed in a gas flow path between said inlet port and said interior chamber, said primary valve member opening in response to an external signal to permit pressurized fluid to flow from said inlet port into said interior chamber, 
 a primary outlet port having a first end opening into said interior chamber and a second end in fluid communication with said inflatable evacuation slide defining a gas flow path from said interior chamber to said inflatable evacuation slide, and 
 a gas relief valve in fluid communication with said a gas flow path between said interior chamber of said control valve and said inflatable evacuation slide, said gas relief valve having a vent port opening into a region external to said valve body, said gas relief valve further comprising a valve member and a thermal actuator, said thermal actuator operating to move said valve member from a fully closed position at a first temperature to a fully open position at a second temperature said thermal actuator further operating to move said valve member to a partially closed position at a temperature intermediate said first and second temperatures, wherein said valve is capable of moving from said partially closed position to said fully closed position in response to temperature without moving to said fully open position. 
 
 
   
   
     2. An inflatable aircraft evacuation slide system comprising:
 an inflatable evacuation slide stored in an undeployed condition; 
 a source of inflation gas for inflating said inflatable evacuation slide; 
 a control valve, said control valve comprising;
 a valve body defining an interior chamber and an inlet port in fluid communication with said source of inflation gas, 
 a primary valve member, said primary valve member disposed in a gas flow path between said inlet port and said interior chamber, said primary valve member opening in response to an external signal to permit pressurized fluid to flow from said inlet port into said interior chamber, 
 a primary outlet port having a first end opening into said interior chamber and a second end in fluid communication with said inflatable evacuation slide defining a gas flow path from said interior chamber to said inflatable evacuation slide, and 
 
 a gas relief valve in fluid communication with said a gas flow path between said interior chamber of said control valve and said inflatable evacuation slide, said gas relief valve having a vent port opening into a region external to said valve body, said gas relief valve further comprising a valve member and a thermal actuator, said thermal actuator operating to move said valve member to obstruct said vent port with decreasing temperature and to move said valve member to open said vent port with increasing temperature, wherein: 
 said thermal actuator operates to move said valve member a distance that is proportional to temperature. 
 
   
   
     3. The inflatable aircraft evacuation slide system of  claim 2 , wherein:
 said thermal actuator operates to move said valve member from 0.0001 to 0.001 inches per degree Fahrenheit. 
 
   
   
     4. The inflatable aircraft evacuation slide system of  claim 3 , wherein:
 said thermal actuator operates to move said valve member from 0.0006 to 0.0008 inches per degree Fahrenheit. 
 
   
   
     5. The inflatable aircraft evacuation slide system of  claim 1 , wherein:
 said thermal actuator comprises a housing, an expanding element and a piston, said housing having a bore adapted to contain said expanding element, said piston having a first end disposed in and slidingly engaging said bore and a second end engaging said valve member, wherein said expanding element expands. 
 
   
   
     6. The inflatable aircraft evacuation slide system of  claim 1 , wherein:
 said vent port has a flow area of zero square inches at −65 degrees Fahrenheit and a flow area of 0.3 square inches at +160 degrees Fahrenheit.